如果我的防火墙关闭了，还有什么可能阻止访问 mysql？

Question

我想远程访问我的 mysql 服务器，但是当我从我的电脑 telnet 服务器时，我得到了这个

C:\Users\USER>telnet 197.000.0.00 3306
Connecting To 197.000.0.00...Could not open connection to the host, on port 3306
: Connect failed

和这个

C:\Users\USER>telnet 197.000.0.00
Connecting To 197.000.0.00...Could not open connection to the host, on port 23:
Connect failed

我也尝试过 nmap

C:\Users\USER>nmap -PN -p 3306 197.000.0.00

Starting Nmap 6.47 ( http://nmap.org ) at 2014-09-16 09:59 
Nmap scan report for 197.000.0.00
Host is up.
PORT     STATE    SERVICE
3306/tcp filtered mysql

Nmap done: 1 IP address (1 host up) scanned in 39.66 seconds

我也关闭了所有防火墙

[root@globan globan]# service ip6tables status
ip6tables: Firewall is not running.
[root@globan globan]# service iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables:[  OK  ]
[root@globan globan]# service iptables stop
iptables: Setting chains to policy ACCEPT: filter          [  OK  ]
iptables: Flushing firewall rules:                         [  OK  ]
iptables: Unloading modules:                               [  OK  ]
[root@globan globan]# chkconfig iptables off
[root@globan globan]# service iptables status
iptables: Firewall is not running.
[root@globan globan]#

我也做了 netstat

[root@globan globan]# netstat -tapnl | grep 3306
tcp        0      0 0.0.0.0:3306                0.0.0.0:*                   LIST
EN      21517/mysqld
[root@globan globan]#

我的操作系统是centos。

即使防火墙已关闭，我仍无法成功 telnet 我的服务器，原因可能是什么？